The Physical Disk performance object monitors physical disk. It identifies the instances representing the physical hardware, the LUN present to the host and the counters are the sum of the access to all partitions on the physical instance.
From Storage perspective, the main two performance measurements we care about are Throughput and Latency.
Throughput: How many IO transactions can the array complete in a second? Or how many MB of data blocks are processed by the array for a given second. IOPS or MB/s unit of measurement used depends on the type of IO.
Latency: How long does the array take to finish an IO operation?
Those measurements could all be found in Physical Disk performance objects in Perfmon.
Using Performance Monitor:
To start Performance Monitor:
1. Click Start, click in the Start Search box, type perfmon , and press ENTER.
2. In the navigation tree, expand Monitoring Tools, and then click Performance Monitor.
3. Click Add Counters (Ctrl+N), in the dialog box, expand Physical Disk objects.
4. Select the Performance counters and Physical disk in Select counter from computerand Instances of select object dialog box:
5. Click OK
Physical Disk Counters Explained:
Throughput IOPS Counters:
Disk Transfers/sec = Total I/O per second
Disk Reads/sec = Total Read I/O per second
Disk Writes/sec = Total Write I/O per second
Above counters basically explains that Perfmon captures the total number of individual disk IO requests completed over a period of one second. If the Perfmon capture interval is set for anything greater than one second, the average of the values captured is presented. Disk Reads/sec and Disk Writes/sec are calculated in the same way, but break down the results in read requests only or write requests only, respectively.
Throughput MB/s Counters:
Disk Bytes/sec = Total number of bytes per second
Disk Read Bytes/sec = Total number of read bytes per second
Disk Write Bytes/sec = Total number of write bytes per second
Above counters means the Perfmon captures the total number of bytes sent to the disk (write) and retrieved from the disk (read) over a period of one second. If the Perfmon capture interval is set for anything greater than one second, the average of the values captured is presented. The Disk Read Bytes/sec and the Disk Write Bytes/sec counters break down the results displaying only read bytes or only write bytes, respectively.
Latency Counters (Disk Response Time):
Avg. Disk sec/Transfer = Average Disk Response Time per I/O
Avg. Disk sec/Read = Average Disk Response Time per read I/O
Avg. Disk sec/Write = Average Disk Response Time per write I/O
Above counters used to measure the I/O latency that display the average time the disk transfers took to complete, in seconds. Although the scale is seconds, the counter has millisecond precision, meaning a value of 0.004 indicates the average time for disk transfers to complete was 4 milliseconds.
Configure Perfmon display:
To configure the Performance Monitor display:
- Right-click in the Performance Monitor display area and click Properties.
- Make the desired configuration changes.
- To see the effect of your changes without re-opening the Propertiesdialog box, you can click Apply after any modification.
- When you are finished, click OK.
To save the current Performance Monitor display as a web page
- Right-click in the Performance Monitor display area and click Save Settings As .
- Choose a directory where you want to save the file.
- Type a name for the saved display file, and then click OK.
For more information refer to EMC solution article “000169539”